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Add to My Garden Common sunflower
Helianthus annuus
Also known as: Annual sunflower
The common sunflower is recognizable for its bright flower on a very tall stem. It is often grown in gardens. These flowers have been important in culture: they were worshipped by the ancient Inca people, and today, they represent eco-friendly movements. The artist Vincent Van Gogh made a famous series of paintings about common sunflowers. Wild versions of the plant branch out to many flower heads, but domesticated plants typically only have one.
Twice per week
Water
Full sun
Sunlight
Weeds
Care Guide for Common sunflower
Common sunflower requires infrequent but deep watering in order to help its roots grow. The key growth period is three weeks before and after flowering; at this time the plant should be watered weekly until the topsoil is moist.
Common sunflower draws all of its nutrient needs from the soil, so it only requires fertilization if it is planted in very poor soils. If this is the case then add a slow-release granular fertilizer, but be sure to apply it in moderation since over-fertilization can cause its stem to become weak and break.
Trim the diseased, withered leaves once a month.
Loam, Sand, Clay, Chalky, Neutral, Alkaline
Needs excellent drainage in pots.
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Common sunflower
Water
Twice per week
Sunlight
Full sun
Hardiness Zones
4 - 8
Planting Time
Spring, Summer
Download and print this plant care card and attach it to your plants
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Common sunflower
Water
Twice per week
Sunlight
Full sun
Hardiness Zones
4 - 8
Planting Time
Spring, Summer
Download
Common sunflower
Water
Twice per week
Sunlight
Full sun
Hardiness Zones
4 - 8
Planting Time
Spring, Summer
Download
Questions About Common sunflower
Watering 
Pruning 
Seasonal Care How Often to Water Common sunflower?
Common sunflower needs water regularly throughout the growing season. Beginning in spring, you should plan to water this plant about once per week. As the season presses on and grows warmer, you may need to increase your watering rate to about two to three times per week. Exceeding at this rate can be detrimental to your Common sunflower. With that said, you should also ensure that the soil in which your Common sunflower grows remains relatively moist but not wet, regardless of how often you must water to make that the case. Watering Common sunflower that lives in a pot is a bit different. Generally, you'll need to increase your watering frequency, as the soil in a pot can heat up and dry out a bit faster than ground soil. As such, you should plan to water a container-grown Common sunflower a few times per week in most cases, versus just once per week for an in-ground plant.
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How Much to Water Common sunflower?
There are a few different ways you can go about determining how much water to give to your Common sunflower. Some gardeners choose to pick their water volume based on feeling the soil for moisture. That method suggests that you should water until you feel that the first six inches of soil have become moist. Alternatively, you can use a set measurement to determine how much to water your Common sunflower. Typically, you should give your Common sunflower about two gallons of water per week, depending on how hot it is and how quickly the soil becomes dry. However, following strict guidelines like that can lead to overwatering if your plant requires less than two gallons per week for whatever reason. When growing Common sunflower in a container, you will need to use a different method to determine how much water to supply. Typically, you should give enough water to moisten all of the layers of soil that have become dry. To test if that is the case, you can simply stick your finger in the soil to feel for moisture. You can also water the soil until you notice a slight trickle of excess water exiting the drainage holes of your pot.
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What Is the Best Way to Water the Common sunflower?
To water Common sunflower, you can use a garden hose with a spray nozzle, a watering can, or just about any other common watering tool. Generally, Common sunflower is not too picky about how they receive their water, as they can live off of rainwater, tap water, or filtered water. Often, you should try not to water this plant from overhead, as doing so can damage the leaves and flowers and may lead to disease as well. At times, the best method for watering this plant is to set up a drip irrigation system. These systems work well for Common sunflower as they apply water evenly and directly to the soil. For one Common sunflower that grows in a container, you can use a similar watering approach while changing the tools you use. To water a container-grown Common sunflower, use a cup, watering can, or your tap to apply water directly to the soil.
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How to Know If You Are Watering Common sunflower Enough?
It can be somewhat difficult to avoid overwatering your Common sunflower. On the one hand, these plants have relatively deep roots that require you to moisten the soil weekly. On the other hand, Common sunflower are plants that are incredibly susceptible to root rot. Along with root rot, your Common sunflower may also experience browning as a result of overwatering. Underwatering is far less likely for your Common sunflower as these plants can survive for a while in the absence of supplemental watering. However, if you go too long without giving this plant water, it will likely begin to wilt. You may also notice dry leaves.
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What to Do If Your Water Common sunflower Too Much or Too Little?
The remedy for underwatering Common sunflower is somewhat obvious. When you notice that your plant lacks moisture, simply begin watering it on a more regular basis. The issue of overwatering can be a much more dire situation, especially if you fail to notice it early. When your Common sunflower is overwatered, it may contract diseases that lead to its decline and death. The best way to prevent this outcome is to choose a proper growing location, one that receives plenty of sunlight to help dry the soil and has good enough drainage to allow excess water to drain rather than pooling and causing waterlogged soils. If you overwater your Common sunflower that lives in a pot, you may need to consider changing it to a new pot. Your previous container may not have contained soil with good drainage or may not have had sufficient drainage holes. As you repot your overwatered Common sunflower, make sure to add loose soils and to use a pot that drains efficiently.
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How to Water Common sunflower Through the Seasons?
You can expect your Common sunflower’s water needs to increase as the season moves on. During spring, you should water about once per week. Then, as the summer heat arrives, you will likely need to give a bit more water to your Common sunflower, at times increasing to about three times per week. This is especially true of Common sunflower that grow in containers, as the soil in a container is far more likely to dry out faster than ground soil when the weather is warm. In autumn, while your Common sunflower is still in bloom, it may need a bit less water as the temperature has likely declined, and the sun is no longer as strong as it was in summer.
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How to Water Common sunflower at Different Growth Stages?
Common sunflower will move through several different growth stages throughout the year, some of which may require more water than others. For example, you will probably start your Common sunflower as a seed. While the seed germinates, you should plant to give more water than your Common sunflower will need later in life, watering often enough to maintain consistent soil moisture. After a few weeks, your Common sunflower will grow above the soil and may need slightly less water than at the seedling phase. Then, once this plant is mature, you can begin to use the regular watering frequency of about once per week. As flower development takes place, you may need to give slightly more water to aid the process.
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What'S the Difference between Watering Common sunflower Indoors and Outdoors?
There are several reasons why most Common sunflower grow outdoors rather than indoors. The first is that these plants typically grow to tall. The second reason is that Common sunflower needs more daily sunlight than most indoor growing locations can provide. If you are able to provide a suitable indoor growing location, you may find that you need to give your Common sunflower water a bit more often than you would in an outdoor growing location. Part of the reason for this is that indoor growing locations tend to be a lot drier than outdoor ones due to HVAC units. The other reason for this is that soil in containers can dry out relatively quickly as well compared to soil in the ground.
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Common Pests & Diseases
Common issues for Common sunflower based on 10 million real cases
Leaf beetles
Leaf beetles are a class of colored insects 1 - 2 cm in size. They gnaw on leaves and petals resulting in small, round holes scattered over the surface.
Solutions: For less serious cases: Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread. To treat more serious infestations: Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions. Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.
Caterpillars
Caterpillars are fleshy moth or butterfly larvae that come in an array of colors, patterns, and even hairstyles. They chew on leaves and flower petals, creating large, irregular holes.
Solutions: Even though caterpillars are diverse, they all chew on plant parts and can cause significant damage if present in large numbers. For severe cases: Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects. Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans. Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps. For less severe cases: Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water. Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.
Sap-sucking insects
Sap-sucking insects can create dense clusters of small yellow or white spots on the leaves.
Solutions: Sap-sucking insects can be hard to spot, as they are often small and attach to the undersides of plant leaves. If you see signs of an infestation, follow these steps to eradicate it. Hand-pick bugs and remove eggs: Inspect your plants for insects and drop any you find in a container of soapy water. Look carefully at the undersides of plant leaves and squish any egg clusters you find. Use Insecticide: Targeted spraying can take out sap-sucking insects. Small infestations can be controlled with insecticidal soap, though larger outbreaks might require a stronger spray. Introduce natural predators: Many insects, including ladybugs and praying mantises, love to feast on sap-suckers. You can purchase them at garden stores and release them near infected plants, or encourage wild ones by creating habitat space.
Brown spot
This infection can cause brown spots or patches to appear on the plant.
Solutions: In minor cases of brown spot, there isn’t any need to treat the disease. However, if much of the foliage is affected and defoliation occurs, the plant will benefit from getting rid of the infection. It is recommended to start by applying organic treatment options, working up to the more potent synthetic, chemical fungicides if necessary. Organic options won’t kill the fungus, but will prevent it from spreading. Dissolve ½ teaspoon of baking soda and one teaspoon of liquid soap in a gallon of water. Using a spray bottle, spray on tops and bottoms of leaves until the mixture drips off. Repeat every two weeks until existing spots stop enlarging and new spots no longer appear. Spray a copper-based fungicidal soap on the leaves, coating the top and bottom leaf surfaces. Reapply as directed on the product label. Copper penetrates the leaf surface and prevents germination of spores so the fungus cannot spread. Apply an all-purpose fungicide to the entire plant, following the label instructions carefully.
Leaf rot
This pathogen can cause the leaves to rot.
Solutions: Bacterial infections need to be treated quickly to prevent the spread to neighboring, healthy plants, potentially wiping out large sections of your indoor or outdoor garden. In mild cases: Use sterilized (10% bleach solution) pruning shears or scissors to remove any infected plant parts, making sure to dispose of them off site. Use a copper-based bactericide to treat the unaffected foliage, as well as the soil, and neighboring plants. Follow the manufacturer’s rate and timing directions found on the product label. In severe cases, where more than half the leaves are affected: Remove all of the infected plants from the garden, disposing of them off site. Treat the soil and neighboring plants using a copper-based bactericide. Follow the manufacturer’s rate and timing directions found on the product label.
Plant dried up
The entire plant may dry out due to dieback or normal seasonal dormancy.
Solutions: The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method. Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly. Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems. Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species. Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil. Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.
Keep your leafy friends healthy and happy.
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Leaf beetles
Leaf beetles are a class of colored insects 1 - 2 cm in size. They gnaw on leaves and petals resulting in small, round holes scattered over the surface.
Overview
Leaf beetles range in size from 1.5 mm to 2 cm. Both adult beetles and their larvae eat the leaves of many different types of plants. There are over 35,000 different species of leaf beetles, in a variety of colors including gold, green, yellow-striped, and red striped. Some of these have been mistaken for ladybirds because of their shape and coloring. They can be oval, round, or elongated in shape. These insect pests are most active in spring and summer.
If not controlled, leaf beetles can do a lot of damage to vegetable crops and ornamental plants. They feed on the leaves, flowers, stems, roots, and fruits of different plants. They can fly, which means it's easy for them to move from one plant to another. Some species of leaf beetles only target one specific crop, while others will target many different types of plants. Although a lot of the damage that they cause is cosmetic, an infestation can weaken a plant and leave it prone to other more problematic diseases.
Symptom Analysis
The first signs of a leaf beetles infestation are small visible holes in leaves. Leaves then become discolored and dark beetle droppings can be seen. As the leaves turn yellow and brown, they will drop off the plant onto the ground. Some leaves will appear skeletonized with only the veins still remaining.
Infestation begins in spring, when the adult beetles emerge from the soil and lay their eggs on the leaves of plants. When these eggs hatch, the young nymphs start munching on the leaves as they grow up. Once leaf beetles are large and mature, they'll fall to the ground and pupate in the soil over winter before starting the cycle all over again.
Leaf beetles also eat holes in fruits and vegetables. These can be seen as small round holes that sometimes have a larger brown area surrounding them.
Solutions
For less serious cases:
- Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread.
To treat more serious infestations:
- Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions.
- Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.
Prevention
To prevent infestations of leaf beetles, follow these practices.
- Regularly check for beetles. To prevent large pest infestations, be proactive about frequently checking plants for pests and removing them quickly.
- Clear debris. Clear weeds and debris to remove areas where these beetles may overwinter and hide.
- Attract natural predators. Birds and other insects, such as wasps and ladybugs, are effective natural predators of leaf beetles. Encourage them to visit by including a diverse array of plants to provide habitat and food. Also, avoid applying broad-spectrum herbicides that can harm and kill beneficial insects.
- Plant aromatic herbs like mint, garlic, or rosemary, as these can repel leaf beetles.
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Caterpillars
Caterpillars are fleshy moth or butterfly larvae that come in an array of colors, patterns, and even hairstyles. They chew on leaves and flower petals, creating large, irregular holes.
Overview
Caterpillars can cause problems for home gardeners. If not managed, these insects can defoliate a plant in just a matter of days. However, home gardeners face a challenge because these caterpillars eventually turn into beautiful butterflies and moths, which are important for pollination and the general ecosystem.
There are thousands of different species of caterpillars and many will only target certain plants. If caterpillars are posing a problem, they can be removed by hand, or gardeners can use insect-proof netting to protect their valuable plants.
Symptom Analysis
Caterpillars are the larvae of butterflies and moths. During the warmer months, butterflies and moths that visit gardens will lay their eggs on the underside of leaves.
When the tiny eggs hatch, the young larvae emerge and start feeding on the leaves of the plant. Depending on how many larvae have hatched, they can easily defoliate the plant in a very short period of time. Caterpillars will shed their skin as they grow, around 4 or 5 times during this feeding cycle.
Symptoms of caterpillars eating plants appear as holes in the leaves. The edges of the leaves may be eaten away as well, and flowers can be affected as well.
Some are easy to see, but others need to be searched for. This is because their bodies are often camouflaged to look like part of the plant. Gardeners need to look carefully along the stems of the plant as well as under the leaves. Also, look for tiny white, yellow, or brown eggs that can be found in groups on the underside of leaves.
Once the caterpillar is fully grown, it transforms into a pupa or chrysalis. Then, after a period of time that varies according to the species, a butterfly or moth will emerge from the pupa and the cycle begins again.
Solutions
Even though caterpillars are diverse, they all chew on plant parts and can cause significant damage if present in large numbers.
For severe cases:
- Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects.
- Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans.
- Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps.
For less severe cases:
- Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water.
- Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.
Prevention
Prevention may require less effort than attempts to eradicate infestations that have already begun. Here are our top steps for prevention:
- Monitor plants. Check plants regularly for caterpillar eggs on leaves. If they do not belong to an endangered species, they should be squished.
- Use insect netting. Cover plants with insect netting to prevent butterflies and moths from laying eggs on plants.
- Apply diatomaceous earth. Apply DE to plants early in the season and reapply after rain.
- Encourage plant diversity. This will attract predatory insects including parasitic wasps.
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Sap-sucking insects
Sap-sucking insects can create dense clusters of small yellow or white spots on the leaves.
Symptom Analysis
Your plant has developed tiny yellowish spots scattered across the leaves that look like mold or mildew. If these marks won't wipe off, they are likely caused by sap-sucking insects like aphids, squash bugs, scale bugs, leafhoppers, whiteflies, mites, mealybugs, and more.
Each of these pests uses mouthparts to pierce leaf tissues and suck the sap. uses mouthparts to pierce leaf tissues and suck the sap. Signs of damage are difficult to spot at first, but a large infestation can quickly compromise the whole plant. You're most likely to see sap-sucking insects during the hottest months because plants make easier targets when already weakened from heat or drought.
Though sap-sucking insects are unlikely to kill your plant on their own, they can severely weaken it and make it more susceptible to disease. They may also spread viruses from one plant to another as they feed.
Solutions
Sap-sucking insects can be hard to spot, as they are often small and attach to the undersides of plant leaves. If you see signs of an infestation, follow these steps to eradicate it.
- Hand-pick bugs and remove eggs: Inspect your plants for insects and drop any you find in a container of soapy water. Look carefully at the undersides of plant leaves and squish any egg clusters you find.
- Use Insecticide: Targeted spraying can take out sap-sucking insects. Small infestations can be controlled with insecticidal soap, though larger outbreaks might require a stronger spray.
- Introduce natural predators: Many insects, including ladybugs and praying mantises, love to feast on sap-suckers. You can purchase them at garden stores and release them near infected plants, or encourage wild ones by creating habitat space.
Prevention
Healthy plants are less likely to suffer from sap-sucker attacks. Keep them fortified with fertilizer and the right amounts of water and sunlight. Plants that receive excess nitrogen are also more susceptible to attack, so don’t overfertilize. You should also remove weeds and tall grasses surrounding your outdoor plants so as not to create habitat space for the pests.
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Brown spot
This infection can cause brown spots or patches to appear on the plant.
Overview
Discolored spots on the foliage of plants are one of the most common disease problems people observe. These spots are caused by fungal and bacterial diseases, with most infections related to a fungal pathogen.
Brown spot can occurs on all houseplants, flowering ornamentals, vegetable plants, and leaves of trees, bushes, and shrubs. No plants are resistant to it, and the problem is worse in warm, wet environments. It can occur at any point in the life stage as long as leaves are present.
Small brownish spots appear on the foliage and enlarge as the disease progresses. In severe cases, the plant or tree is weakened when the lesions interrupt photosynthesis or cause defoliation.
Symptom Analysis
In most cases, brown spot only affects a small percentage of the whole plant, appearing on a small amount of the leaves. A small infection only puts minor stress on the plant. However, if left untreated and the disease progresses over numerous seasons, it will severely impact the health and productivity of the infected specimen.
- Sporulation begins (reproduction of the fungal spores), and tiny spots appear on leaves.
- Placement is often random and scattered as diseases are spread through raindrops.
- May appear on lower leaves and the interior of the plant where humidity is higher.
- Brown spots enlarge and grow large enough to touch neighboring spots to form a more prominent blotch.
- Leaf margins may turn yellow.
- Tiny black dots (fruiting bodies of the fungi) appear in the dead spots.
- Blotches grow in size until the entire leaf is brown.
- The leaf falls off the plant.
Severe Symptoms
- Partial or complete premature defoliation
- Reduced growth
- Increased susceptibility to pests and other diseases
Disease Cause
Brown spot, or leaf spot, is a common descriptive term given to several diseases affecting the leaves of plants and trees. Around 85% of diseases exhibiting leaf spots are due to fungus or fungus-like organisms. Sometimes brown spot is caused by a bacterial infection, or insect activity with similar symptoms.
When conditions are warm and the leaf surfaces are wet, fungal spores being transported by wind or rain land on the surface and cling to it. They do not rupture the cell walls but grow in the space between the plant plasma membrane and the plant cell wall. As the spores reproduce, they release toxins and enzymes that cause necrotic spots (i.e., dead tissue) on the leaves, allowing the fungi to consume the products released when the cells degrade.
Solutions
In minor cases of brown spot, there isn’t any need to treat the disease. However, if much of the foliage is affected and defoliation occurs, the plant will benefit from getting rid of the infection. It is recommended to start by applying organic treatment options, working up to the more potent synthetic, chemical fungicides if necessary.
Organic options won’t kill the fungus, but will prevent it from spreading.
- Dissolve ½ teaspoon of baking soda and one teaspoon of liquid soap in a gallon of water. Using a spray bottle, spray on tops and bottoms of leaves until the mixture drips off. Repeat every two weeks until existing spots stop enlarging and new spots no longer appear.
- Spray a copper-based fungicidal soap on the leaves, coating the top and bottom leaf surfaces. Reapply as directed on the product label. Copper penetrates the leaf surface and prevents germination of spores so the fungus cannot spread.
- Apply an all-purpose fungicide to the entire plant, following the label instructions carefully.
Prevention
Like many other diseases, it is easier to prevent brown spot than cure it, and this is done through cultural practices.
- Clear fall leaves from the ground before winter to minimize places where fungi and bacteria can overwinter.
- Maintain good air movement between plants through proper plant spacing.
- Increase air circulation through the center of plants through pruning.
- Thoroughly clean all pruning tools after working with diseased plants.
- Never dispose of disease plant material in a compost pile.
- Avoid overhead watering to keep moisture off of the foliage.
- Keep plants healthy by providing adequate sunlight, water, and fertilizer.
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Leaf rot
This pathogen can cause the leaves to rot.
Overview
Leaf rot is very common among both house plants and garden plants. It affects foliage and occurs mainly when the leaves become wet due to rain or misting by the gardener. The cause is fungal disease and this is facilitated by the fungal spores adhering to wet leaves then penetrating the leaf and expanding rapidly. Damp conditions and poor air circulation will increase chances of infection taking place. Another factor are leaves that are damaged or have been penetrated by sap sucking insects that facilitate plant penetration.
Symptom Analysis
- Spores are able to cling to a damp leaf and penetrate, often through an existing wound.
- A small dark brown mark appears which expands rapidly as sporulation starts to take place.
- Quite quickly these bull's eye like circles can link together and the whole leaf turns dark and loses texture.
- Leaf drop occurs.
Disease Cause
These symptoms are caused by a bacterial infection invading the plant. Bacteria from many sources in the environment (air, water, soil, diseased plants) enter a plant through wounds, or in some cases the stomata when they are open. Once inside the leaf tissue, the bacteria feed and reproduce quickly, breaking down healthy leaves.
Bacterial infections threaten most plant species, and are more prominent in wet weather that more easily transfers the bacteria from plant to plant, or from soil to plant.
Solutions
Bacterial infections need to be treated quickly to prevent the spread to neighboring, healthy plants, potentially wiping out large sections of your indoor or outdoor garden.
In mild cases: Use sterilized (10% bleach solution) pruning shears or scissors to remove any infected plant parts, making sure to dispose of them off site. Use a copper-based bactericide to treat the unaffected foliage, as well as the soil, and neighboring plants. Follow the manufacturer’s rate and timing directions found on the product label.
In severe cases, where more than half the leaves are affected: Remove all of the infected plants from the garden, disposing of them off site. Treat the soil and neighboring plants using a copper-based bactericide. Follow the manufacturer’s rate and timing directions found on the product label.
Prevention
- Clean up garden debris at the end of the season, especially if it contains any diseased plant tissue. Diseases can overwinter from season to season and infect new plants.
- Avoid overhead watering to prevent transferring pathogens from one plant to another, and to keep foliage dry.
- Mulch around the base of plants to prevent soil-borne bacteria from splashing up onto uninfected plants.
- Sterilize cutting tools using a 10% bleach solution when gardening and moving from one plant to another.
- Do not work in your garden when it is wet.
- Rotate crops to prevent the buildup of bacteria in one site due to continuous cropping.
- Use a copper or streptomycin-containing bactericide in early spring to prevent infection. Read label directions carefully as they are not suitable for all plants.
- Ensure plants are well spaced and thin leaves on densely leaved plants so that air circulation is maximised.
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Plant dried up
The entire plant may dry out due to dieback or normal seasonal dormancy.
Symptom Analysis
Your plant has dried out and turned brown. It might be starting to wilt, with no noticeable green around the stems and leaves. Touch the leaves, and they may crinkle under your fingers.
Possible causes of a dried out plant include:
- Not enough water. A lack of water will lead to dry plant tissue.
- Too much water. Watering too much can lead to root rot which makes the plant struggle to take up water. Rotted, mushy roots are a sign of overeating.
- Entering dormancy. As perennial plants enter their resting period known as dormancy, their leaves dry out and may fall off. This happens during decreasing day length.
- Exposure to herbicides and other toxic substances. If a plant is hit with a large dose herbicide or other toxic chemical, the plant will turn brown.
- Too much fertility. An excess of fertilizer can prevent plants from taking up water, leading to drying.
- Improper sun exposure. Just like humans, plants can get sunburn by intense, direct light. Plants can also dry out if they don’t receive enough light.
To determine whether the plant is still alive and can be saved, you can:
- Bend a stem. If the stem is pliable, the plant is still alive. If the stem breaks, the plant is dead.
- Gently scratch the stem with your fingernail for signs of green inside. If your plant is dead, the stem will be brittle and brown throughout.
- Cut the stems back a little bit a time for visible green growth. If none of the stems have visible green growth, the plant is dead.
Solutions
The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method.
- Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly.
- Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems.
- Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species.
- Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil.
- Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.
Prevention
Prevention involves providing your plant with the proper environment.
- Provide the proper amount of water. The amount of water depends on a plant’s size, species, and environment. A general rule is to allow soil to dry out between waterings.
- Place plants in the proper environment. Provide the proper hours of sun and temperature for your individual plant.
- Provide proper fertility. Most plants only need to be fertilized once or twice a year; don’t overapply.
- Keep plants free from toxic substances. Keep herbicides and toxic household chemicals away from your plants.
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Weed Control
Weeds
While some cultivars and hybrids of common sunflower (Helianthus annuus) are grown as ornamental plants or as oil crops, the wild form is considered an agricultural weed in Europe, including Spain, France and the Balkan countries. It is also listed as a noxious weed in the US state of Iowa. The plant's weedy form is distinguished by its strong branching and multiple flower heads. There are several reasons why common sunflower is considered an agricultural weed. It has high water needs, plus it grows tall and rapidly. It has a tendency to self-seed and grow freely on disturbed land, including the edges of corn, soy, and commercial sunflower fields, drawing water and nutrients away from the desired crops. Intensive herbicide use in maize fields can render weedy common sunflower herbicide-resistant.
How to Control it
The best time to remove weeds is before bearing fruits. Pulling out: For a kind of herb, wear gloves or use tools to dig weeds. Pruning: For an annual plant, pruning its aboveground parts can effectively control the growth. Plowing: Plow the soil before cultivation and bury the whole weed in the soil. Chemical control: If in large amounts, weeds can be removed by the herbicide.
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Distribution Map
Habitat
Plains
Native
Cultivated
Invasive
Potentially invasive
Exotic
No species reported
More Info
Plant Type
Herb
Flower Color
Yellow
Orange
Red
Brown
Bloom Time
Summer, Fall
Leaf Color
Green
Name story
Common sunflower
Generally, most people think that the naming of sunflower is based on the direction of sunrise and sunset. However, this is not the case. Matured sunflower will only face the East and it will not rotate with the direction of the sun. Nevertheless, the misconception of it facing the sun has embedded deeply in people's mind. Hence, it is called common sunflower.
Symbolism
Silent love, admiration, loyalty, long life, good fortune
Usages
Artistic Value
The common sunflower is often the subject of music, poetry and paintings. The most famous painting is Van Gogh's Sunflower.
Environmental Protection Value
It can purify the metal content of the soil.
Garden Use
The bright and beautiful common sunflower is a common annual in sunny home gardens. The tall stalks and large sunny blooms make it a beautiful backdrop to many other low-growing flowers in cottage and prairie/meadow gardens. Beans and squash are good veggies to grow with sunflowers, as they help balance the pH in the soil.
Scientific Classification
Related Plants
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Indian coral tree (Erythrina variegata) is a tropical and sub-tropical shade tree often planted singly in wide-open landscaping areas. It flowers in spring, and its seedpods are poisonous. Indian coral tree flowers are important symbols in Sri Lankan New Year traditions are also considered the official flower of Okinawa. The wood has economic value and is often used as a construction material.
Montbretia
Montbretia (Crocosmia crocosmiiflora) is a hybrid flowering plant native to France. The Latin name Crocosmia crocosmiiflora is derived from the Greek word "krokus" (saffron) and "osme" (smell). This plant's dried flowers smell of saffron when hot water is added to them.
Tievine
Ipomoea cordatotrilobais a type of weed native to the southeastern United States, Mexico, and South America. Tievine has one heart-shaped leaf, and one leaf with three lobes. The flowers vary from pink to lavender to dark purple with five distinct lines that some say resemble a star pattern. Tievine is considered an invasive species in some areas.
Basket plant
The basket plant is a common houseplant. It doesn't require much light to grow. Its tiny flowers are white and have a pleasant scent. If grown in intense sunlight the leaves will often turn purplish.
Indian shot
Despite its name, indian shot (Canna indica) is a flowering perennial plant native to Central and South America. It has been naturalized in other parts of the world and became a popular garden plant for its large decorative leaves, fiery red blooms, and the ease of cultivation. It is a traditional minor food crop for indigenous peoples of the Americas.
Man to man
Man to man (Peperomia pellucida) is a perennial flowering plant that blooms all year. The entire man to man plant is edible and can be eaten raw or cooked.
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Care Guide
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Pests & Diseases
Weed Control
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Add to My Garden Common sunflower
Helianthus annuus
Also known as: Annual sunflower
Twice per week
Water
Full sun
Sunlight
Weeds
Care Guide for Common sunflower
Water
Common sunflower requires infrequent but deep watering in order to help its roots grow. The key growth period is three weeks before and after flowering; at this time the plant should be watered weekly until the topsoil is moist.
Fertilization
Common sunflower draws all of its nutrient needs from the soil, so it only requires fertilization if it is planted in very poor soils. If this is the case then add a slow-release granular fertilizer, but be sure to apply it in moderation since over-fertilization can cause its stem to become weak and break.
Pruning
Trim the diseased, withered leaves once a month.
Soil
Loam, Sand, Clay, Chalky, Neutral, Alkaline
Potting Suggestions
Needs excellent drainage in pots.
Tips, advice, and instructions for over 13,000 species that you will find nowhere else
Common sunflower
Helianthus annuus
Water
Twice per week
Sunlight
Full sun
Hardiness Zones
4 - 8
Planting Time
Spring, Summer
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Questions About Common sunflower
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Common Pests & Diseases
Common issues for Common sunflower based on 10 million real cases
Leaf beetles
Leaf beetles are a class of colored insects 1 - 2 cm in size. They gnaw on leaves and petals resulting in small, round holes scattered over the surface.
Solutions: For less serious cases: Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread. To treat more serious infestations: Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions. Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.
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Caterpillars
Caterpillars are fleshy moth or butterfly larvae that come in an array of colors, patterns, and even hairstyles. They chew on leaves and flower petals, creating large, irregular holes.
Solutions: Even though caterpillars are diverse, they all chew on plant parts and can cause significant damage if present in large numbers. For severe cases: Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects. Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans. Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps. For less severe cases: Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water. Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.
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Sap-sucking insects
Sap-sucking insects can create dense clusters of small yellow or white spots on the leaves.
Solutions: Sap-sucking insects can be hard to spot, as they are often small and attach to the undersides of plant leaves. If you see signs of an infestation, follow these steps to eradicate it. Hand-pick bugs and remove eggs: Inspect your plants for insects and drop any you find in a container of soapy water. Look carefully at the undersides of plant leaves and squish any egg clusters you find. Use Insecticide: Targeted spraying can take out sap-sucking insects. Small infestations can be controlled with insecticidal soap, though larger outbreaks might require a stronger spray. Introduce natural predators: Many insects, including ladybugs and praying mantises, love to feast on sap-suckers. You can purchase them at garden stores and release them near infected plants, or encourage wild ones by creating habitat space.
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Brown spot
This infection can cause brown spots or patches to appear on the plant.
Solutions: In minor cases of brown spot, there isn’t any need to treat the disease. However, if much of the foliage is affected and defoliation occurs, the plant will benefit from getting rid of the infection. It is recommended to start by applying organic treatment options, working up to the more potent synthetic, chemical fungicides if necessary. Organic options won’t kill the fungus, but will prevent it from spreading. Dissolve ½ teaspoon of baking soda and one teaspoon of liquid soap in a gallon of water. Using a spray bottle, spray on tops and bottoms of leaves until the mixture drips off. Repeat every two weeks until existing spots stop enlarging and new spots no longer appear. Spray a copper-based fungicidal soap on the leaves, coating the top and bottom leaf surfaces. Reapply as directed on the product label. Copper penetrates the leaf surface and prevents germination of spores so the fungus cannot spread. Apply an all-purpose fungicide to the entire plant, following the label instructions carefully.
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Leaf rot
This pathogen can cause the leaves to rot.
Solutions: Bacterial infections need to be treated quickly to prevent the spread to neighboring, healthy plants, potentially wiping out large sections of your indoor or outdoor garden. In mild cases: Use sterilized (10% bleach solution) pruning shears or scissors to remove any infected plant parts, making sure to dispose of them off site. Use a copper-based bactericide to treat the unaffected foliage, as well as the soil, and neighboring plants. Follow the manufacturer’s rate and timing directions found on the product label. In severe cases, where more than half the leaves are affected: Remove all of the infected plants from the garden, disposing of them off site. Treat the soil and neighboring plants using a copper-based bactericide. Follow the manufacturer’s rate and timing directions found on the product label.
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Plant dried up
The entire plant may dry out due to dieback or normal seasonal dormancy.
Solutions: The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method. Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly. Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems. Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species. Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil. Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.
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Diagnose your plant, and learn how to prevent and treat plant diseases.
Leaf beetles
Leaf beetles are a class of colored insects 1 - 2 cm in size. They gnaw on leaves and petals resulting in small, round holes scattered over the surface.
Overview
Leaf beetles range in size from 1.5 mm to 2 cm. Both adult beetles and their larvae eat the leaves of many different types of plants. There are over 35,000 different species of leaf beetles, in a variety of colors including gold, green, yellow-striped, and red striped. Some of these have been mistaken for ladybirds because of their shape and coloring. They can be oval, round, or elongated in shape. These insect pests are most active in spring and summer.
If not controlled, leaf beetles can do a lot of damage to vegetable crops and ornamental plants. They feed on the leaves, flowers, stems, roots, and fruits of different plants. They can fly, which means it's easy for them to move from one plant to another. Some species of leaf beetles only target one specific crop, while others will target many different types of plants. Although a lot of the damage that they cause is cosmetic, an infestation can weaken a plant and leave it prone to other more problematic diseases.
Symptom Analysis
The first signs of a leaf beetles infestation are small visible holes in leaves. Leaves then become discolored and dark beetle droppings can be seen. As the leaves turn yellow and brown, they will drop off the plant onto the ground. Some leaves will appear skeletonized with only the veins still remaining.
Infestation begins in spring, when the adult beetles emerge from the soil and lay their eggs on the leaves of plants. When these eggs hatch, the young nymphs start munching on the leaves as they grow up. Once leaf beetles are large and mature, they'll fall to the ground and pupate in the soil over winter before starting the cycle all over again.
Leaf beetles also eat holes in fruits and vegetables. These can be seen as small round holes that sometimes have a larger brown area surrounding them.
Solutions
For less serious cases:
- Remove beetles, nymphs, and eggs. Remove all life stages of the beetles and kill them by placing them in a bucket of warm, soapy water. This can be done more easily by placing the bucket under affected leaves and shaking the plant. This method is most effective in the afternoon when leaf beetles are more active. Always dispose of insects in a sealed bag or container to avoid escape and spread.
To treat more serious infestations:
- Apply organic insecticides. Use naturally-derived insecticides before moving on to synthetic insecticides. Neem oil and pyrethrum are naturally-derived insecticides that should be applied following label instructions.
- Apply synthetic insecticides. Examples of insecticides effective for leaf beetles include carbaryl, permethrin, and bifenthrin. Apply insecticides according to label instructions.
Prevention
To prevent infestations of leaf beetles, follow these practices.
- Regularly check for beetles. To prevent large pest infestations, be proactive about frequently checking plants for pests and removing them quickly.
- Clear debris. Clear weeds and debris to remove areas where these beetles may overwinter and hide.
- Attract natural predators. Birds and other insects, such as wasps and ladybugs, are effective natural predators of leaf beetles. Encourage them to visit by including a diverse array of plants to provide habitat and food. Also, avoid applying broad-spectrum herbicides that can harm and kill beneficial insects.
- Plant aromatic herbs like mint, garlic, or rosemary, as these can repel leaf beetles.
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Caterpillars
Caterpillars are fleshy moth or butterfly larvae that come in an array of colors, patterns, and even hairstyles. They chew on leaves and flower petals, creating large, irregular holes.
Overview
Caterpillars can cause problems for home gardeners. If not managed, these insects can defoliate a plant in just a matter of days. However, home gardeners face a challenge because these caterpillars eventually turn into beautiful butterflies and moths, which are important for pollination and the general ecosystem.
There are thousands of different species of caterpillars and many will only target certain plants. If caterpillars are posing a problem, they can be removed by hand, or gardeners can use insect-proof netting to protect their valuable plants.
Symptom Analysis
Caterpillars are the larvae of butterflies and moths. During the warmer months, butterflies and moths that visit gardens will lay their eggs on the underside of leaves.
When the tiny eggs hatch, the young larvae emerge and start feeding on the leaves of the plant. Depending on how many larvae have hatched, they can easily defoliate the plant in a very short period of time. Caterpillars will shed their skin as they grow, around 4 or 5 times during this feeding cycle.
Symptoms of caterpillars eating plants appear as holes in the leaves. The edges of the leaves may be eaten away as well, and flowers can be affected as well.
Some are easy to see, but others need to be searched for. This is because their bodies are often camouflaged to look like part of the plant. Gardeners need to look carefully along the stems of the plant as well as under the leaves. Also, look for tiny white, yellow, or brown eggs that can be found in groups on the underside of leaves.
Once the caterpillar is fully grown, it transforms into a pupa or chrysalis. Then, after a period of time that varies according to the species, a butterfly or moth will emerge from the pupa and the cycle begins again.
Solutions
Even though caterpillars are diverse, they all chew on plant parts and can cause significant damage if present in large numbers.
For severe cases:
- Apply insecticide. For an organic solution, spray plants with a Bacillus thuringiensis (Bt), which specifically affects the larval stage of moths and butterflies. Be sure to coat plants, since caterpillars need to ingest Bt for it to be effective. This will not harm other insects.
- Spray a chili extract. Chili seeds can be cooked in water to make a spicy spray that caterpillars don't like. Spray this mixture on the plants, but be aware it will also be spicy to humans.
- Introduce beneficial insects. Release beneficial insects to the garden that eat caterpillars, such as parasitic wasps.
For less severe cases:
- Hand pick. Using gloves, pick off caterpillars on plants and dispose of them in a bucket of soapy water.
- Dust plants with diatomaceous earth. This powder is harmless to humans but irritates caterpillars. Therefore, it will make it difficult for caterpillars to move and eat.
Prevention
Prevention may require less effort than attempts to eradicate infestations that have already begun. Here are our top steps for prevention:
- Monitor plants. Check plants regularly for caterpillar eggs on leaves. If they do not belong to an endangered species, they should be squished.
- Use insect netting. Cover plants with insect netting to prevent butterflies and moths from laying eggs on plants.
- Apply diatomaceous earth. Apply DE to plants early in the season and reapply after rain.
- Encourage plant diversity. This will attract predatory insects including parasitic wasps.
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Sap-sucking insects
Sap-sucking insects can create dense clusters of small yellow or white spots on the leaves.
Symptom Analysis
Your plant has developed tiny yellowish spots scattered across the leaves that look like mold or mildew. If these marks won't wipe off, they are likely caused by sap-sucking insects like aphids, squash bugs, scale bugs, leafhoppers, whiteflies, mites, mealybugs, and more.
Each of these pests uses mouthparts to pierce leaf tissues and suck the sap. uses mouthparts to pierce leaf tissues and suck the sap. Signs of damage are difficult to spot at first, but a large infestation can quickly compromise the whole plant. You're most likely to see sap-sucking insects during the hottest months because plants make easier targets when already weakened from heat or drought.
Though sap-sucking insects are unlikely to kill your plant on their own, they can severely weaken it and make it more susceptible to disease. They may also spread viruses from one plant to another as they feed.
Solutions
Sap-sucking insects can be hard to spot, as they are often small and attach to the undersides of plant leaves. If you see signs of an infestation, follow these steps to eradicate it.
- Hand-pick bugs and remove eggs: Inspect your plants for insects and drop any you find in a container of soapy water. Look carefully at the undersides of plant leaves and squish any egg clusters you find.
- Use Insecticide: Targeted spraying can take out sap-sucking insects. Small infestations can be controlled with insecticidal soap, though larger outbreaks might require a stronger spray.
- Introduce natural predators: Many insects, including ladybugs and praying mantises, love to feast on sap-suckers. You can purchase them at garden stores and release them near infected plants, or encourage wild ones by creating habitat space.
Prevention
Healthy plants are less likely to suffer from sap-sucker attacks. Keep them fortified with fertilizer and the right amounts of water and sunlight. Plants that receive excess nitrogen are also more susceptible to attack, so don’t overfertilize. You should also remove weeds and tall grasses surrounding your outdoor plants so as not to create habitat space for the pests.
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Brown spot
This infection can cause brown spots or patches to appear on the plant.
Overview
Discolored spots on the foliage of plants are one of the most common disease problems people observe. These spots are caused by fungal and bacterial diseases, with most infections related to a fungal pathogen.
Brown spot can occurs on all houseplants, flowering ornamentals, vegetable plants, and leaves of trees, bushes, and shrubs. No plants are resistant to it, and the problem is worse in warm, wet environments. It can occur at any point in the life stage as long as leaves are present.
Small brownish spots appear on the foliage and enlarge as the disease progresses. In severe cases, the plant or tree is weakened when the lesions interrupt photosynthesis or cause defoliation.
Symptom Analysis
In most cases, brown spot only affects a small percentage of the whole plant, appearing on a small amount of the leaves. A small infection only puts minor stress on the plant. However, if left untreated and the disease progresses over numerous seasons, it will severely impact the health and productivity of the infected specimen.
- Sporulation begins (reproduction of the fungal spores), and tiny spots appear on leaves.
- Placement is often random and scattered as diseases are spread through raindrops.
- May appear on lower leaves and the interior of the plant where humidity is higher.
- Brown spots enlarge and grow large enough to touch neighboring spots to form a more prominent blotch.
- Leaf margins may turn yellow.
- Tiny black dots (fruiting bodies of the fungi) appear in the dead spots.
- Blotches grow in size until the entire leaf is brown.
- The leaf falls off the plant.
Severe Symptoms
- Partial or complete premature defoliation
- Reduced growth
- Increased susceptibility to pests and other diseases
Disease Cause
Brown spot, or leaf spot, is a common descriptive term given to several diseases affecting the leaves of plants and trees. Around 85% of diseases exhibiting leaf spots are due to fungus or fungus-like organisms. Sometimes brown spot is caused by a bacterial infection, or insect activity with similar symptoms.
When conditions are warm and the leaf surfaces are wet, fungal spores being transported by wind or rain land on the surface and cling to it. They do not rupture the cell walls but grow in the space between the plant plasma membrane and the plant cell wall. As the spores reproduce, they release toxins and enzymes that cause necrotic spots (i.e., dead tissue) on the leaves, allowing the fungi to consume the products released when the cells degrade.
Solutions
In minor cases of brown spot, there isn’t any need to treat the disease. However, if much of the foliage is affected and defoliation occurs, the plant will benefit from getting rid of the infection. It is recommended to start by applying organic treatment options, working up to the more potent synthetic, chemical fungicides if necessary.
Organic options won’t kill the fungus, but will prevent it from spreading.
- Dissolve ½ teaspoon of baking soda and one teaspoon of liquid soap in a gallon of water. Using a spray bottle, spray on tops and bottoms of leaves until the mixture drips off. Repeat every two weeks until existing spots stop enlarging and new spots no longer appear.
- Spray a copper-based fungicidal soap on the leaves, coating the top and bottom leaf surfaces. Reapply as directed on the product label. Copper penetrates the leaf surface and prevents germination of spores so the fungus cannot spread.
- Apply an all-purpose fungicide to the entire plant, following the label instructions carefully.
Prevention
Like many other diseases, it is easier to prevent brown spot than cure it, and this is done through cultural practices.
- Clear fall leaves from the ground before winter to minimize places where fungi and bacteria can overwinter.
- Maintain good air movement between plants through proper plant spacing.
- Increase air circulation through the center of plants through pruning.
- Thoroughly clean all pruning tools after working with diseased plants.
- Never dispose of disease plant material in a compost pile.
- Avoid overhead watering to keep moisture off of the foliage.
- Keep plants healthy by providing adequate sunlight, water, and fertilizer.
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Leaf rot
This pathogen can cause the leaves to rot.
Overview
Leaf rot is very common among both house plants and garden plants. It affects foliage and occurs mainly when the leaves become wet due to rain or misting by the gardener. The cause is fungal disease and this is facilitated by the fungal spores adhering to wet leaves then penetrating the leaf and expanding rapidly. Damp conditions and poor air circulation will increase chances of infection taking place. Another factor are leaves that are damaged or have been penetrated by sap sucking insects that facilitate plant penetration.
Symptom Analysis
- Spores are able to cling to a damp leaf and penetrate, often through an existing wound.
- A small dark brown mark appears which expands rapidly as sporulation starts to take place.
- Quite quickly these bull's eye like circles can link together and the whole leaf turns dark and loses texture.
- Leaf drop occurs.
Disease Cause
These symptoms are caused by a bacterial infection invading the plant. Bacteria from many sources in the environment (air, water, soil, diseased plants) enter a plant through wounds, or in some cases the stomata when they are open. Once inside the leaf tissue, the bacteria feed and reproduce quickly, breaking down healthy leaves.
Bacterial infections threaten most plant species, and are more prominent in wet weather that more easily transfers the bacteria from plant to plant, or from soil to plant.
Solutions
Bacterial infections need to be treated quickly to prevent the spread to neighboring, healthy plants, potentially wiping out large sections of your indoor or outdoor garden.
In mild cases: Use sterilized (10% bleach solution) pruning shears or scissors to remove any infected plant parts, making sure to dispose of them off site. Use a copper-based bactericide to treat the unaffected foliage, as well as the soil, and neighboring plants. Follow the manufacturer’s rate and timing directions found on the product label.
In severe cases, where more than half the leaves are affected: Remove all of the infected plants from the garden, disposing of them off site. Treat the soil and neighboring plants using a copper-based bactericide. Follow the manufacturer’s rate and timing directions found on the product label.
Prevention
- Clean up garden debris at the end of the season, especially if it contains any diseased plant tissue. Diseases can overwinter from season to season and infect new plants.
- Avoid overhead watering to prevent transferring pathogens from one plant to another, and to keep foliage dry.
- Mulch around the base of plants to prevent soil-borne bacteria from splashing up onto uninfected plants.
- Sterilize cutting tools using a 10% bleach solution when gardening and moving from one plant to another.
- Do not work in your garden when it is wet.
- Rotate crops to prevent the buildup of bacteria in one site due to continuous cropping.
- Use a copper or streptomycin-containing bactericide in early spring to prevent infection. Read label directions carefully as they are not suitable for all plants.
- Ensure plants are well spaced and thin leaves on densely leaved plants so that air circulation is maximised.
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Plant dried up
The entire plant may dry out due to dieback or normal seasonal dormancy.
Symptom Analysis
Your plant has dried out and turned brown. It might be starting to wilt, with no noticeable green around the stems and leaves. Touch the leaves, and they may crinkle under your fingers.
Possible causes of a dried out plant include:
- Not enough water. A lack of water will lead to dry plant tissue.
- Too much water. Watering too much can lead to root rot which makes the plant struggle to take up water. Rotted, mushy roots are a sign of overeating.
- Entering dormancy. As perennial plants enter their resting period known as dormancy, their leaves dry out and may fall off. This happens during decreasing day length.
- Exposure to herbicides and other toxic substances. If a plant is hit with a large dose herbicide or other toxic chemical, the plant will turn brown.
- Too much fertility. An excess of fertilizer can prevent plants from taking up water, leading to drying.
- Improper sun exposure. Just like humans, plants can get sunburn by intense, direct light. Plants can also dry out if they don’t receive enough light.
To determine whether the plant is still alive and can be saved, you can:
- Bend a stem. If the stem is pliable, the plant is still alive. If the stem breaks, the plant is dead.
- Gently scratch the stem with your fingernail for signs of green inside. If your plant is dead, the stem will be brittle and brown throughout.
- Cut the stems back a little bit a time for visible green growth. If none of the stems have visible green growth, the plant is dead.
Solutions
The solution for a dried out plant depends on the cause, so determine the cause before selecting a treatment method.
- Adjust your watering: Stick your finger in the soil near the roots. If it feels bone dry or overly saturated, you need to adjust your watering frequency accordingly.
- Prune back dead foliage: Snip off any brown stems and leaves on the plant to make space for new growth. This encourages the roots to send up fresh stems.
- Move to a proper environment. This may involve decreasing or increasing sun exposure, depending on the species.
- Decrease fertilizer applications. If you have applied too much fertilizer, you can repot plants with fresh potting soil.
- Wait. If your plant has dried out as daylight is decreasing, it is entering dormancy. Decrease watering and wait until the plant resumes growth.
Prevention
Prevention involves providing your plant with the proper environment.
- Provide the proper amount of water. The amount of water depends on a plant’s size, species, and environment. A general rule is to allow soil to dry out between waterings.
- Place plants in the proper environment. Provide the proper hours of sun and temperature for your individual plant.
- Provide proper fertility. Most plants only need to be fertilized once or twice a year; don’t overapply.
- Keep plants free from toxic substances. Keep herbicides and toxic household chemicals away from your plants.
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Weed Control
Weeds
While some cultivars and hybrids of common sunflower (Helianthus annuus) are grown as ornamental plants or as oil crops, the wild form is considered an agricultural weed in Europe, including Spain, France and the Balkan countries. It is also listed as a noxious weed in the US state of Iowa. The plant's weedy form is distinguished by its strong branching and multiple flower heads. There are several reasons why common sunflower is considered an agricultural weed. It has high water needs, plus it grows tall and rapidly. It has a tendency to self-seed and grow freely on disturbed land, including the edges of corn, soy, and commercial sunflower fields, drawing water and nutrients away from the desired crops. Intensive herbicide use in maize fields can render weedy common sunflower herbicide-resistant.
How to Control it
The best time to remove weeds is before bearing fruits. Pulling out: For a kind of herb, wear gloves or use tools to dig weeds. Pruning: For an annual plant, pruning its aboveground parts can effectively control the growth. Plowing: Plow the soil before cultivation and bury the whole weed in the soil. Chemical control: If in large amounts, weeds can be removed by the herbicide.
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Distribution Map
Habitat
Plains
Map
Native
Cultivated
Invasive
Potentially invasive
Exotic
No species reported
More Info
Plant Type
Herb
Flower Color
Yellow
Orange
Red
Brown
Bloom Time
Summer, Fall
Leaf Color
Green
Name story
Common sunflower
Generally, most people think that the naming of sunflower is based on the direction of sunrise and sunset. However, this is not the case. Matured sunflower will only face the East and it will not rotate with the direction of the sun. Nevertheless, the misconception of it facing the sun has embedded deeply in people's mind. Hence, it is called common sunflower.
Symbolism
Silent love, admiration, loyalty, long life, good fortune
Usages
Artistic Value
The common sunflower is often the subject of music, poetry and paintings. The most famous painting is Van Gogh's Sunflower.
Environmental Protection Value
It can purify the metal content of the soil.
Garden Use
The bright and beautiful common sunflower is a common annual in sunny home gardens. The tall stalks and large sunny blooms make it a beautiful backdrop to many other low-growing flowers in cottage and prairie/meadow gardens. Beans and squash are good veggies to grow with sunflowers, as they help balance the pH in the soil.
Scientific Classification
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